Scientists have so far confirmed 5,084 exoplanets in 3,811 star systems, with 8,912 candidates waiting to be confirmed. These findings provide a detailed sample of the types of planets that exist in the universe, from gas giants several times the size of Jupiter to smaller planets like Earth. rocky planet.
Most exoplanets are discovered through indirect methods, such as the transit method and the radial velocity method. Using the National Science Foundation’s Very Long Baseline Interferometer Array (VLBA), research scientists recently detected a Jupiter-like planet orbiting a binary star system called GJ 896A b, about 20 light-years from Earth. The research team used “astrometry” to discover planets. When orbiting the star of the system, gravity also pulls the star at the same time, and the existence of the binary star “wobble” is inferred. This method even allows the team to build a three-dimensional structure to describe the operation of the entire binary star system. situation.
GJ 896AB is two red dwarf stars orbiting each other. The larger one is orbited by the exoplanet GJ 896A b, with a mass of about 44% of the sun, and the smaller one is only 17% of the sun. The distance between the two stars is about 30 AU (about the distance from the sun to Neptune), and the orbital period is 229 years. The orbit of a planet orbiting a larger star is slightly smaller than the distance from Venus to the sun. The orbital period is about 284 days. The intersection angle of the star’s orbital orbit is 148 degrees, which means that the movement of the planet around the main star is opposite to that of the secondary star. The researchers say this is the first time scientists have observed this dynamic structure in a planet close to a binary star system, which may have formed in the same protoplanetary disk.
Astrometry will become a tool for delineating more planetary systems in the future, thanks to observatories such as the Next Generation Very Large Array (ngVLA), the paper is published in the Astronomical Journal.
(This article is reproduced with permission from the Taipei Planetarium; source of the first image: Sophia Dagnello / NRAO / AUI / NSF)
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